Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;

import static java.lang.Math.max;
import static java.lang.Math.min;

/**
 * Created by stepank on 13.07.2017.
 */
public class TaskD {

    public static void main(String[] args) throws Exception {
        long startTime = System.currentTimeMillis();
        try (InputReader in = new InputReader(System.in);
             PrintWriter out = new PrintWriter(System.out)) {
            new TaskD().solve(in, out);
        }
        System.err.println(System.currentTimeMillis() - startTime);
    }

    private void solve(InputReader in, PrintWriter out) {
        int n = in.nextInt();
        int m = in.nextInt();
        int[][] a = new int[n][m];
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < m; ++j) {
                a[i][j] = in.nextInt();
            }
        }
        int steps = 0;
        StringBuilder answer = new StringBuilder();
        if (n < m) {
            for (int i = 0; i < n; ++i) {
                while (true) {
                    boolean yet = true;
                    for (int j = 0; j < m; ++j) {
                        if (a[i][j] == 0) {
                            yet = false;
                        }
                    }
                    if (!yet) {
                        break;
                    }
                    answer.append("row ").append(i + 1).append("\n");
                    ++steps;
                    for (int j = 0; j < m; ++j) {
                        a[i][j]--;
                    }
                }
            }
            for (int j = 0; j < m; ++j) {
                while (true) {
                    boolean yet = true;
                    for (int i = 0; i < n; ++i) {
                        if (a[i][j] == 0) {
                            yet = false;
                        }
                    }
                    if (!yet) {
                        break;
                    }
                    answer.append("col ").append(j + 1).append("\n");
                    ++steps;
                    for (int i = 0; i < n; ++i) {
                        a[i][j]--;
                    }
                }
            }
        } else {
            for (int j = 0; j < m; ++j) {
                while (true) {
                    boolean yet = true;
                    for (int i = 0; i < n; ++i) {
                        if (a[i][j] == 0) {
                            yet = false;
                        }
                    }
                    if (!yet) {
                        break;
                    }
                    answer.append("col ").append(j + 1).append("\n");
                    ++steps;
                    for (int i = 0; i < n; ++i) {
                        a[i][j]--;
                    }
                }
            }
            for (int i = 0; i < n; ++i) {
                while (true) {
                    boolean yet = true;
                    for (int j = 0; j < m; ++j) {
                        if (a[i][j] == 0) {
                            yet = false;
                        }
                    }
                    if (!yet) {
                        break;
                    }
                    answer.append("row ").append(i + 1).append("\n");
                    ++steps;
                    for (int j = 0; j < m; ++j) {
                        a[i][j]--;
                    }
                }
            }
        }
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < m; ++j) {
                if (a[i][j] > 0) {
                    out.print(-1);
                    return;
                }
            }
        }
        out.println(steps);
        out.print(answer);
    }


    private static class InputReader implements AutoCloseable {

        private final BufferedReader reader;
        private StringTokenizer tokenizer;

        public InputReader(InputStream inputStream) {
            reader = new BufferedReader(new InputStreamReader(inputStream));
        }

        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return tokenizer.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }


        @Override
        public void close() throws Exception {
            reader.close();
        }
    }

}